[issue10806] Subprocess error if fds 0,1,2 are closed
Antoine Pitrou pit...@free.fr added the comment: This new patch makes tests more comprehensive (closes all combinations of the three standard fds). -- Added file: http://bugs.python.org/file20242/sp3.patch ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue10806 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue10806] Subprocess error if fds 0,1,2 are closed
Antoine Pitrou pit...@free.fr added the comment: Committed in r87695 (3.2), r87696 (3.1) and r87697 (2.7). -- resolution: - fixed stage: - committed/rejected status: open - closed versions: +Python 2.7, Python 3.1 ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue10806 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue10806] Subprocess error if fds 0,1,2 are closed
New submission from Ross Lagerwall rosslagerw...@gmail.com:
There is an issue where if a python program closes all the std. file
descriptors (e.g. a daemon) and then uses the subprocess module, the file
descriptors may not be set up properly in the subprocess. This may actually be
a fairly common use case in a daemon program that needs to run a subprocess and
set up pipes to it.
Here is an example:
import os, subprocess, sys
x=os.open('/dev/null', os.O_RDWR)
os.close(0)
os.close(1)
os.close(2)
res = subprocess.Popen([sys.executable, -c,
'import sys;'
'sys.stdout.write(apple);'
'sys.stdout.flush();'
'sys.stderr.write(orange)'],
stdin=x,
stdout=subprocess.PIPE,
stderr=subprocess.PIPE).communicate()
with open('/tmp/out', 'w') as f:
f.write(repr(res) + '\n')
f.write(repr((b'apple', b'orange')) + '\n')
The expected output in /tmp/out is:
('apple', 'orange')
('apple', 'orange')
but we get:
(b'', bFatal Python error: Py_Initialize: can't initialize sys standard
streams\nOSError: [Errno 9] Bad file descriptor\n)
(b'apple', b'orange')
The problem comes about where the calls are made (this applies to the python
c versions):
os.dup2(p2cread, 0)
os.dup2(c2pwrite, 1)
os.dup2(errwrite, 2)
if c2pwrite or p2cread or errwrite is the same as what it's being dupped() to
(eg if c2pwrite == 1) then the dup2 call does nothing. But, if we're using
pipes, the close-on-exec flags are set initially and the dup2() call would
normally remove the flag but it doesn't.
Attached is a patch which basically uses fcntl if necessary to remove the
close-on-exec flag, and tests.
--
components: Library (Lib)
files: subprocess.patch
keywords: patch
messages: 125067
nosy: georg.brandl, giampaolo.rodola, gregory.p.smith, pitrou, rosslagerwall
priority: normal
severity: normal
status: open
title: Subprocess error if fds 0,1,2 are closed
type: behavior
versions: Python 3.2
Added file: http://bugs.python.org/file20223/subprocess.patch
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[issue10806] Subprocess error if fds 0,1,2 are closed
Antoine Pitrou pit...@free.fr added the comment: Attached is a patch which basically uses fcntl if necessary to remove the close-on-exec flag, and tests. Python adds extra output at the end of stderr when compiled in debug mode. Therefore you first have to strip that output, like this: out, err = subprocess.Popen(...).communicate() err = support.strip_python_stderr(err) self.assertEqual((out, err), (b'apple', b'orange')) Otherwise, looks good, thank you. -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue10806 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue10806] Subprocess error if fds 0,1,2 are closed
Ross Lagerwall rosslagerw...@gmail.com added the comment: Updated patch for debug mode. Does this also need to be applied for 3.1? -- Added file: http://bugs.python.org/file20228/subprocess_v2.patch ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue10806 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue10806] Subprocess error if fds 0,1,2 are closed
Antoine Pitrou pit...@free.fr added the comment: Updated patch for debug mode. Does this also need to be applied for 3.1? Yes, but we can port it ourselves (unless you're really motivated) -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue10806 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue10806] Subprocess error if fds 0,1,2 are closed
Antoine Pitrou pit...@free.fr added the comment: Patch works fine, thank you. Here is an attempt at a slightly more readable code by refactoring. -- Added file: http://bugs.python.org/file20230/sp.patch ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue10806 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue10806] Subprocess error if fds 0,1,2 are closed
Antoine Pitrou pit...@free.fr added the comment: This further patch also addresses issue9905 (incorporating Ross' tests). -- Added file: http://bugs.python.org/file20234/sp2.patch ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue10806 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue10806] Subprocess error if fds 0,1,2 are closed
STINNER Victor victor.stin...@haypocalc.com added the comment: See also #6610 which has a patch with another test. -- nosy: +haypo ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue10806 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
